In today's print on demand, a print job can be generated, which may contain several pages of text and images of various complexities. These complex jobs can heavily require and occupy long processing time (i.e., raster image processing or “RIP” time) on the printing device. In sequences of print jobs, this can become a bottleneck for other jobs waiting to be processed or RIPped as the printing device has to complete ripping of the current complex job before it can proceed to the subsequent print job.
For example, a print job describes in a form of PDL (Page Description Language) such as PostScript language file, which contains sets of instructions telling the printer how to lay pixel or dots onto a page to be printed. The PDL file is processed by a RIP (Raster Image Processor) processor(s). RIP processed page is often called a rasterized page. Every rasterized page will be temporarily stored in print memory until release to print engine. Accumulation of rasterized pages can easily occupy large amount of memory space while waiting to be printed. This can occur on a print job which may contain many pages consisting of mixed data of text, images, graphics and colors of various complexities. For example, it is common to produce rasterized page the size of 100 MB which could be a thousand times larger than in its PDL form. In U.S. Patent Publication No. 2007/0052998 A1, the application discloses controlling the output timing of the rasterized pages to minimize down time of the print engine. While this approach can reduced print engine down time, there can be many rasterized pages being held temporarily which can occupy large amounts of memory space in the printer for the duration of the delay of the page output timing to the print engine.